A missing return statement that previously did not have a visibly negative
effect caused after some data-structure changes in r248024 multi-dimensional
accesses to be modeled both multi-dimensional as well as linearized. This
commit adds the missing return to avoid the incorrect double modeling as
well as the compile time increases it caused.
llvm-svn: 248171
If we encounter a <nsw> tagged AddRec for a loop we know the trip count of
that loop has to be bounded or the semantics is undefined anyway. Hence, we
only need to add unbounded assumptions if no such AddRec is known.
llvm-svn: 248128
So far we ignored the unbounded parts of the iteration domain, however
we need to assume they do not occure at all to remain sound if they do.
llvm-svn: 248126
We now add loop carried information during the second traversal of the
region instead of in a intermediate step in-between. This makes the
generation simpler, removes code and should even be faster.
llvm-svn: 248125
In order to allow multiple back edges we:
- compute the conditions under which each back edge is taken
- build the union over all these conditions, thus the condition that
any back edge is taken
- apply the same logic to the union we applied to a single back edge
llvm-svn: 248120
As we currently do not perform any optimizations that targets (or is
even aware) small trip counts we will skip them when we count the
loops in a region.
llvm-svn: 248119
All MemoryAccess objects will be owned by ScopInfo::AccFuncMap which
previously stored the IRAccess objects. Instead of creating new
MemoryAccess objects, the already created ones are reused, but their
order might be different now. Some fields of IRAccess and MemoryAccess
had the same meaning and are merged.
This is the last step of fusioning TempScopInfo.{h|cpp} and
ScopInfo.{h.cpp}. Some refactoring might still make sense.
Differential Revision: http://reviews.llvm.org/D12843
llvm-svn: 248024
In some cases instcombine introduces bitcasts that slightly obfuscate the
multi-dimensionality of an array. This patch teaches our fixed-size
delinearization how to look through bitcasts.
llvm-svn: 247928
This information is implicitly available through the multi-dimensionality of
memory accesses. This reduces compile time for 3mm from 430ms to 400ms and
should generally benefit compile time for cases where the assumed context
is complex.
llvm-svn: 247907
If the GEP instructions give us enough insights, model scalar accesses as
multi-dimensional (and generate the relevant run-time checks to ensure
correctness). This will allow us to simplify the dependence computation in
a subsequent commit.
llvm-svn: 247906
This will allow to generate non-wrap assumptions for integer expressions
that are part of the SCoP. We compare the common isl representation of
the expression with one computed with modulo semantic. For all parameter
combinations they are not equal we can have integer overflows.
The nsw flags are respected when the modulo representation is computed,
nuw and nw flags are ignored for now.
In order to not increase compile time to much, the non-wrap assumptions
are collected in a separate boundary context instead of the assumed
context. This helps compile time as the boundary context can become
complex and it is therefor not advised to use it in other operations
except runtime check generation. However, the assumed context is e.g.,
used to tighten dependences. While the boundary context might help to
tighten the assumed context it is doubtful that it will help in practice
(it does not effect lnt much) as the boundary (or no-wrap assumptions)
only restrict the very end of the possible value range of parameters.
PET uses a different approach to compute the no-wrap context, though lnt runs
have shown that this version performs slightly better for us.
llvm-svn: 247732
Due to the new domain generation, the SCoP keeps track of the domain
for all blocks, thus the SCEVAffinator can now work with blocks to avoid
duplication of the domains.
llvm-svn: 247731
Add polly-check-format as dependency of check-polly if clang-format is
available in the same build.
Differential Revision: http://reviews.llvm.org/D12850
llvm-svn: 247600
Summary:
Make clang-format run on each file independently using
add_custom_format (instead using a shell script in utils/). The targets
polly-{update|check}-format depend on these.
The primary motivation is to make them work on Windows, but also
improves them generally:
- Each file update/check can run in parallel (Although they do not take
long to run anyway)
- Implicit dependency on clang-format, so it recompiles if necessary
- polly-check-format shows the formatting difference if failing
Differential Revision: http://reviews.llvm.org/D12837
llvm-svn: 247581
At some point we build loop trip counts using this method. It was replaced by
a simpler trick that works only for affine (e.g., not modulo) constraints and
relies on the removal of unbounded parts. In order to allow modulo constrains
again we go back to the former, more accurate method.
llvm-svn: 247540
Summary:
TempScop is basically a holder for AccFuncMap, the dictionary from BasicBlocks to IRAccess lists. We move the list into polly::Scop and remove the polly::TempScop class.
There is one small change in behavior: If ScopInfo finds that its AssumedContext is impossible, it bails out by deleting the Scop object. The TempScop::print (invoked with opt -polly-scops -analyze) cannot print the AccFuncMap anymore as it would with a separate TempScop.
Differential Revision: http://reviews.llvm.org/D12803
llvm-svn: 247480
When compiling Polly without LLVM sources but with system-installed
LLVM, the build process would not honor the LLVM_ENABLE_ASSERTIONS
setting LLVM was compiled with, but effectively assume that it is
switched off when compiling. During unit-tests llvm-lit would still
query the LLVM_ENABLE_ASSERTIONS flag and enable tests which require
assertions. Even if enabled for LLVM, Polly does not output its debug
info and statistics in this this mode such that 7 tests fail.
To fix, we query llvm-config --assertion-mode and if on, enable
assertions as HandleLLVMOptions.cmake would do.
We cannot reliably use HandleLLVMOptions.cmake itself as the host's
LLVM build might have been built using automake and distributions
change file locations (e.g. Debian to
/usr/share/llvm-${VERSION}/cmake/HandleLLVMOptions.cmake).
llvm-svn: 247470
The function use_after_scop would iterate from 0 to 1024 and accessing element A[1024] where A has only valid indexes from 0 to 1023. Polly detects the situation of unconditionally undefined behavior and bail out in ScopInfo as non-feasible for optimization.
Other tests add impossible context assumptions as well, hance might show the same problem.
llvm-svn: 247412
Hoist runtime checks in the loop nest if they guard an "error" like event.
Such events are recognized as blocks with an unreachable terminator or a call
to the ubsan function that deals with out of bound accesses. Other "error"
events can be added easily.
We will ignore these blocks when we detect/model/optmize and code generate SCoPs
but we will make sure that they would not have been executed using the assumption
framework.
llvm-svn: 247310
As we do not rely on ScalarEvolution any more we do not need to get
the backedge taken count. Additionally, our domain generation handles
everything that is affine and has one latch and our ScopDetection will
over-approximate everything else.
This change will therefor allow loops with:
- one latch
- exiting conditions that are affine
Additionally, it will not check for structured control flow anymore.
Hence, loops and conditionals are not necessarily single entry single
exit regions any more.
Differential Version: http://reviews.llvm.org/D12758
llvm-svn: 247289
The TempScopInfo (-polly-analyze-ir) pass is removed and its work taken
over by ScopInfo (-polly-scops). Several tests depend on
-polly-analyze-ir and use -polly-scops instead which for the moment
prints the output of both passes. This again is not expected by some
other tests, especially those with negative searches, which have been
adapted.
Differential Version: http://reviews.llvm.org/D12694
llvm-svn: 247288
This patch replaces the last legacy part of the domain generation, namely the
ScalarEvolution part that was used to obtain loop bounds. We now iterate over
the loops in the region and propagate the back edge condition to the header
blocks. Afterwards we propagate the new information once through the whole
region. In this process we simply ignore unbounded parts of the domain and
thereby assume the absence of infinite loops.
+ This patch already identified a couple of broken unit tests we had for
years.
+ We allow more loops already and the step to multiple exit and multiple back
edges is minimal.
+ It allows to model the overflow checks properly as we actually visit
every block in the SCoP and know where which condition is evaluated.
- It is currently not compatible with modulo constraints in the
domain.
Differential Revision: http://reviews.llvm.org/D12499
llvm-svn: 247279
The support for modulo expressions is not comlete and makes the new
domain generation harder. As the currently broken domain generation
needs to be replaced, we will first swap in the new, fixed domain
generation and make it compatible with the modulo expressions later.
llvm-svn: 247278
This prepares for a series of patches that merges TempScopInfo into ScopInfo to
reduce Polly's code complexity. Only ScopInfo.{cpp|h} will be left thereafter.
Moving the code of TempScopInfo in one commit makes the mains diffs simpler to
understand.
In detail, merging the following classes is planned:
TempScopInfo into ScopInfo
TempScop into Scop
IRAccess into MemoryAccess
Only moving code, no functional changes intended.
Differential Version: http://reviews.llvm.org/D12693
llvm-svn: 247274
Johannes Doerfert